Pauli's exclusion principle [1]} enforces high-order correlations
in systems of identical fermions and
its consequences are well known in quantum physics [2]}, [3]}, [4]}.
This principle applies to fermions (such as electrons) and not bosons [5]}.
Pauli's exclusion principle basically states that no two fermions can occupy
the same quantum state and, thus,
anti-symmetrization of the full wave function is required [6]}, [7]}.
Recent work [8]}, [9]}, [10]} focused on confined systems of free fermions
in a harmonic trap argues that quantum correlations imposed by Pauli's exclusion principle
may lead to the stabilization of crystalline structures, called Pauli crystals.
These crystalline structures emerge even when there is
no mutual interaction between fermions.
It was argued that a crystal-like structure is observed
when many identical fermions at very low temperature
are confined within an external two-dimensional (2D) harmonic trap.
The authors of this work [8]}, [9]}, [10]}
showed how to extract these geometric structures
from multiple single-shot pictures of the many-body system
using a numerical approach known as the configuration density technique.
The authors of Ref.[rakshit,gajda1,gajda2] refer to the results
obtained by using the numerical configuration density approach
as "single-shot imaging experiments".
Although we will refer to these works with a similar terminology,
it is our understanding that the works that we just mentioned
are theoretical (they represent computational processing of large data sets).
As far as we know, any experimental verification of the existence
of the Pauli crystals does not exist at the moment.
